Literature Connection:

Sir Cumference and the Dragon of Pi by Cindy Neuschwander

Mathematical Strand:



Students will develop an understanding of measurable attributes of circles; develop a formula to determine the circumference of circles. Students will learn to approximate the value of pi.

Grade Level:


Lesson Created by:

Joe Gelroth, Eugene Field Elementary, Manhattan, KS

LESSON Description


  • Book (Sir Cumference and the Dragon of Pi by Cindy Neuschwander), pencils & paper or a prepared three-column chart for students, measuring tools (rulers, tape measures, string), circular objects, (cups, plates, bowls, CD’s, etc.).

1. Launching the lesson (engage):

  1. Read the story and have the students listen to it - stop after reading The Circle’s Measure on page 13.
  2. Reread and discuss the challenge in The Circle’s Measure.
  3. Demonstrate the method that must be used to solve the riddle by measuring several circular objects. Demonstrate a variety of methods and tools to measure across the middle and around the outside of a circular object. Either provides a variety of circular objects or assign the measuring as homework. Although some students may want to calculate the circumference, insist that the students gather the data by measuring.

2. Developing the lesson:

  1. Have the students measure the diameter ("the middle") and circumference ("the circle around") of several objects.
  2. Have the students divide the circumference by the diameter and find the number. This may require converting fractions to decimals.
  3. After the students have found the ratio, continue to read the story and learn how the story character solved the riddle.

3. Closure/Discussion/Elaboration:

  1. Discuss the history of pi.
  2. Impress upon the students that pi is a never-ending number (as far as we know), but that the exact value of pi is the measure of the distance around a circle divided by the distance across a circle. Circumference divided by diameter.

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Copyright 2001 S.Ma.R.T.Books and Kansas State University